Reproductive Biology of Pipefish Syngnathus typhle and S. abaster (Syngnathidae) from Western Mediterranean Sea

The reproductive biology of two species of pipefish, Syngnathus typhle and S. abaster , was investigated in western Mediterranean coastal waters, through determination of sex-ratio and maturity state, and histological assessment of gonads, brood pouch and embryos of these little-known syngnathid species. A total of 22 S. typhle and 13 S. abaster individuals were collected by towing-net on shallow seagrass meadows ( Posidonia oceanica and Cymodocea nodosa ) at Balearic Islands (Spain). Overall sex-ratio (male : female) was 1.0 : 1.2 for S. typhle and 1.0 : 2.7 for S. abaster . Regarding maturity, all stages of females were sampled while only immature or brooding males were collected. Males with embryos in the pouch were found in summer for both species, and mature females of S. typhle were found in summer whereas mature females of S. abaster were found in winter and summer, suggesting that each species might have a different reproductive cycle. This study contributes to the knowledge on the reproductive biology of the two most abundant pipefish species in W-Mediterranean coastal waters, which might help for further restocking and conservation management strategies.